Mycelium shows potential as sustainable fire-retardant

Associate Professor Tien Huynh, a biotechnology and mycology expert at RMIT University, said they have shown that mycelium can be grown from renewable organic waste.

“Fungi are usually found in a composite form mixed with residual feed material, but we found a way to grow pure mycelium sheets that can be layered and engineered into different uses – from flat panels for the building industry to a leather-like material for the fashion industry,” Huynh said in a statement.

The novel method of creating mycelium sheets that are paper-thin is said to work without pulverising the mycelium’s filament network. Instead, they used different growth conditions and chemicals to make the thin, uniform material. The team’s work is detailed in Polymer Degradation and Stability.

“The great thing about mycelium is that it forms a thermal protective char layer when exposed to fire or radiant heat. The longer and the higher temperature at which mycelium char survives, the better its use as a fireproof material,” said Associate Professor Everson Kandare, co-author of the paper.

Beyond being effective, mycelium-based cladding can be produced from renewable organic waste and is not harmful to the environment when burned, he explained.

Where composite cladding panels are used, they usually contain plastics – which produce toxic fumes and heavy smoke when they burn.

“Bromide, iodide, phosphorus and nitrogen-containing fire retardants are effective, but have adverse health and environmental effects. They pose health and environmental concerns, as carcinogens and neurotoxins that can escape and persist in the environment cause harm to plant and animal life,” said Kandare. “Bioderived mycelium produces naturally occurring water and carbon dioxide.”

This research could eventually lead to improved and eco-friendly cladding for buildings.

“Plastics are quick and easy to produce, whereas fungi is slow to grow and relatively harder to produce at scale,” said Huynh. “However, we’ve been approached by the mushroom industry about using their fungal-incorporated waste products. Collaborating with the mushroom industry would remove the need for new farms while producing products that meet fire safety needs in a sustainable way.”

The researchers are now looking to create fungal mats reinforced by engineering fibres to delay ignition, reduce the flaming intensity and improve fire safety ranking.

This project is a major collaboration involving RMIT University, the University of New South Wales, the Hong Kong Polytechnic University and the Australian Research Council Training Centre in Fire Retardant Materials and Safety Technologies.